Poor stability shall affect the entire board, board will become yellow and the foam sheets'brittleness is large. Insufficient melt strength shall cause the cell of foamed sheet becoming bigger and the longitudinal section bulbs longer. Probably the most direct way to judge whether the melt durability is insufficient is to press the sheet wrapped in the channel speed roll together with your fingertips, if the melt strength is excellent, it is possible to look elasticity when pressing. If it is tough to bounce after pressing, the melt strength is poor then. Because there is much larger difference between a screw structure and cooling method, it is difficult to determine a reasonable temperature. If you want to obtain uniform pvc foam board in the foam pipe, there is must ensure good financial strength of PVC materials also. Foaming help is developed to solve this problem of the foamed article and effectively improve the quality of the foam pipe.
Lubricant is divided into external lubricants and internal lubricants, external slip is certainly conducive to demolding and the surface gloss, if the external slide is much less, it is not an easy task to control and easy heating, which causes the temperature of confluence core, and there will be the nagging problems in the middle of plate, such as a large bubble, string bubble, yellowish, and other concerns. While if the top of plate the precipitation of the external slide isn't smooth; outer slide is considerably more, precipitation will become serious. Inner slide is usually conducive to the fluidity of plasticization and melt, and then it really is difficult to regulate the thickness of structure foam board, if the inner slide is undoubtedly insufficient. If interior slide is too more sufficient, it prone to the phenomenon of big confluence core temperature.
single screw extruder machine
Compared with the aforementioned fundamental problems, the procedure temperature control will be much more intuitive, it's the surface problem, if the heat control isn't good, it could bring about the emergence of the essential problems. Improving the processing heat, material stabilization period will be reduced, and the issues of stability can look; the original lubrication balance shall be broken, the general performance is the insufficient the external lubrication, external lubrication in the late time period especially, there is have to improve the sum of external lubrication; the raising of temperature shall lead to melt strength decreased, cell foam sheet increased, the real amount of cell sheet reduced, the sheet is easy and brittle to break; raise the heat range to reduce the melt strength and decrease the melt viscosity, reducing of the viscosity reduces dispersing potential, for the screw with poor dispersion, usually the phenomenon of uneven dispersion.
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